1. Field of the Invention
The invention relates to bipolar surgical instruments and, more particularly, to bipolar surgical forceps for selectively grasping, manipulating, cutting and/or coagulating body tissue.
2. Description of the Related Art
Electrosurgery involves the cutting or coagulating of body tissue by application of high frequency electrical current. In bipolar electrosurgery, the electrical current is applied through an electrode which contacts the body tissue to be treated. A return electrode is placed in contact with or in close proximity to the current-supplying electrode such that an electrical circuit is formed between the two electrodes. In this manner, the applied electrical current is limited to the body tissue held between the electrodes. When the electrodes are separated from one another, the electrical circuit is open and thus inadvertent contact of body tissue with either of the separated electrodes does not cause current to flow.
To perform tissue cutting, coagulation, or a combination thereof, a high frequency power supply is connected to the bipolar instrument. Each electrode of the bipolar instrument is electrically isolated within the instrument and is separately connected to the high frequency power supply. Typical power supplies such as the SSE2L.TM. available from Valleylab, Inc. of Boulder, Colo., are r.f. generators which can produce different electrical waveforms to effect various electrosurgical procedures. A waveform of continuous sinewaves alternating from positive to negative at the operating frequency of the r.f. generator is employed to cut tissue. Such a waveform creates short, intense electrical sparks to rapidly heat tissue; cells are exploded and the heat dissipated as steam.
A waveform consisting of pulsating sine waves alternating from positive to negative at the operating frequency of the r.f. generator is employed to coagulate tissue. Such a waveform creates longer, less intense sparks which heat tissue less rapidly, allowing heat to be dissipated more widely than during cutting. A combination of the cutting and coagulating waveforms produces the capability to cut tissue with enhanced hemostasis over the pure cutting waveform.
A fuller description concerning the electrical aspects of electrosurgery can be found in the Valleylab SSE2L.TM. Instruction Manual published by Valleylab of Boulder, Colo.
Electrosurgical procedures have, in recent years, become, increasingly widespread. The ease and speed of cutting and/or coagulating tissue saves the surgeon valuable time while minimizing internal bleeding by the patient. Endoscopic and laparoscopic surgical procedures have created additional incentives for the use of electrosurgical techniques. In laparoscopic procedures, surgery is performed in the interior of the abdomen through a small incision; in endoscopic procedures, surgery is performed in any hollow viscus of the body through narrow tubes inserted through small entrance wounds in the skin. Because laparoscopic and endoscopic surgery does not bring the surgeon into direct contact with the operation site, internal bleeding must be quickly controlled by instruments easily operable from a remote location. Electrosurgical instruments provide the surgeon with the ability to electrically cut tissue such that bleeding is minimized and to effectively seal off bleeders during laparascopic and endoscopic procedures. Because laparascopic and endoscopic surgery involve considerable instrument manipulation from a remote location, the actuating mechanism must be convenient to operate once the instrument has been properly positioned.
Thus, a need exists in the art for a bipolar surgical instrument which is readily adaptable for use in laparascopic and endoscopic surgery. Such an instrument must be capable of compact design for fitting through narrow cannulas. Additionally, the instrument must be conveniently actuated by the user. A need also exists for an instrument which can be easily and reliably manufactured from inexpensive materials for single-use applications.